Efforts to enhance the usefulness of magnetic resonance imaging (MRI) in clinical medicine can involve the use of contrast agents. In Phase 1, we identified a ferrite based material which can be used to enhance the detection of hepatic tumors by MRI. We further established that the ferrite based agent was highly detectable by MR and biodegradable. In Phase 2, we shall examine the utility of this contrast agent and related agents to enhance MR images in non- hepatic tissues such as spleen, lung, and bone marrow and in the gastrointestinal tract. Animal models of human diseases will be used to evaluate contrast enhancement in such conditions as abcesses, diffuse splenic disease and focal splenic disease. Studies on the metabolism and toxicity of ferrites will be conducted. Ferrite based agents will also be explored for their ability to enhance volume localization in magnetic resonance spectroscopy. A variety of nontoxic ferrite based contrast agents can be envisioned that will be useful in medical conditions where MRI currently has major shortcomings.